Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B21/00—Layered products comprising a layer of wood, e.g. wood board, veneer, wood particle board
  • B32B21/04—Layered products comprising a layer of wood, e.g. wood board, veneer, wood particle board comprising wood as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B21/08—Layered products comprising a layer of wood, e.g. wood board, veneer, wood particle board comprising wood as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/38—Layered products comprising a layer of synthetic resin comprising epoxy resins
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
  • B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
  • B27N3/002—Manufacture of substantially flat articles, e.g. boards, from particles or fibres characterised by the type of binder
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B21/00—Layered products comprising a layer of wood, e.g. wood board, veneer, wood particle board
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L29/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical; Compositions of hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Compositions of derivatives of such polymers
  • C08L29/02—Homopolymers or copolymers of unsaturated alcohols
  • C08L29/04—Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L97/00—Compositions of lignin-containing materials
  • C08L97/02—Lignocellulosic material, e.g. wood, straw or bagasse
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B15/10—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of wood
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/20—Layered products comprising a layer of metal comprising aluminium or copper
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B21/00—Layered products comprising a layer of wood, e.g. wood board, veneer, wood particle board
  • B32B21/02—Layered products comprising a layer of wood, e.g. wood board, veneer, wood particle board the layer being formed of fibres, chips, or particles, e.g. MDF, HDF, OSB, chipboard, particle board, hardboard
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2260/00—Layered product comprising an impregnated, embedded, or bonded layer wherein the layer comprises an impregnation, embedding, or binder material
  • B32B2260/02—Composition of the impregnated, bonded or embedded layer
  • B32B2260/026—Wood layer
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2260/00—Layered product comprising an impregnated, embedded, or bonded layer wherein the layer comprises an impregnation, embedding, or binder material
  • B32B2260/04—Impregnation, embedding, or binder material
  • B32B2260/046—Synthetic resin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2419/00—Buildings or parts thereof
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2607/00—Walls, panels
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
  • B32B27/322—Layered products comprising a layer of synthetic resin comprising polyolefins comprising halogenated polyolefins, e.g. PTFE

Definitions

• lignocellulosic composite materials useful in structural materials, building materials, furniture components and other uses. More particularly, described herein are new adhesive components used in the manufacture of lignocellulosic composites that provide improved properties to such composites.
• Lignocellulosic composite materials are generally composed of a lignocellulosic material and an adhesive, binder, or resin that are mixed, and then formed by compression molding at high temperatures and pressures. Lignocellulosic composites are used for structural materials, panels, sheathing, moldings, or other building materials. Lignocellulosic composites are also used in furniture components, as painting surfaces for the fine arts, and for other uses.
• lignocellulosic composite materials are made using a formaldehyde-based resin such as urea-formaldehyde, phenol-formaldehyde or melamine-formaldehyde as the adhesive component.
• formaldehyde-based resin such as urea-formaldehyde, phenol-formaldehyde or melamine-formaldehyde
• the industry has recently moved away from formaldehyde-based resins due to evidence that the composite materials formed therefrom release formaldehyde into the environment and may increase the risk of cancer, especially when the materials are used in building interiors.
• MDI Methylene diphenyl diisocyanate
• PMDI polymeric MDI
• MDI is a sensitizer, a suspected carcinogen, and is otherwise harmful to health.
• MDI is the most expensive component of the resulting wood composite, and therefore contributes disproportionately to the expense of the composite material.
• Described herein are adhesive components for lignocellulosic composites that are cheaper, formaldehyde- and MDI-free.
• the technology described herein is easily applicable to existing processing parameters and production equipment.
• a lignocellulosic composite composition comprising: (a) a lignocellulosic component; (b) a bis-electrophile; and (c) a polynucleophile.
• a lignocellulosic composite composition comprising: (a) a lignocellulosic component; (b) a bis-electrophile; (c) a polynucleophile; and (d) an accelerator.
• a method for making a lignocellulosic composition comprising the steps of: (a) applying a polynucleophile to a lignocellulosic component as an aqueous dispersion to form a first intermediate; (b) optionally adjusting the water content of the first intermediate; (c) coating the first intermediate with a bis-electrophile to form a second intermediate; and (d) pressing and heating the second intermediate to form the lignocellulosic composition.
• lignocellulosic component refers to the portion of the composite that consists of lignocellulosic material.
• Lignocellulosic material is typically derived from wood, but also can be derived from other materials, such as straw, flax residue, nut shells, cereal grain hulls, etc.
• the lignocellulosic component is typically wood flour, sawdust, wood strand, wood flakes, wood chips, wood fibers or straw.
• Non-lignocellulosic materials in flake, fibrous or other particulate form, such as glass fiber, mica, asbestos, rubber, plastics, etc. can also be mixed with the lignocellulosic material; however, such materials are not generally required for purposes of the present invention.
• Lignocellulosic composites include chipboards and fiberboard. Fiberboard may be classified as medium density fiberboard (MDF), hardboard, and soft board. Chipboards include particleboard and medium-density particleboard. Fibrous lignocellulosics, such as fibers, flakes, or wood strands, may optionally be oriented in the composite, as for example in “oriented strand boards” (OSB). Lignocellulosic composites also include layered materials, such as plywood, and multilayer fibrous composites, such as multilayer fibrous paper.
• MDF medium density fiberboard
• Chipboards include particleboard and medium-density particleboard.
• Fibrous lignocellulosics such as fibers, flakes, or wood strands, may optionally be oriented in the composite, as for example in “oriented strand boards” (OSB).
• Lignocellulosic composites also include layered materials, such as plywood, and multilayer fibrous composites, such as multilayer fibrous paper.
• an accelerator refers to an optional component of the lignocellulosic composite that can accelerate the composite-forming process.
• An accelerator of the invention is a waxy acid or fatty acid, and may also be a wax/organic acid mixture.
• adheresive component refers to the component of the lignocellulosic composite that consists of a bis-electrophile and a polynucleophile.
• bis-electrophile refers to a molecule with two electrophilic regions, i.e., two portions of the molecule that are attracted to electron-rich (nucleophilic) regions, or are electron-pair receptors.
• Bis-electrophiles include diketones, diesters, dianhydrides, and polyanhydrides.
• polynucleophile refers to a molecule with two or more nucleophilic regions, i.e., two portions of the molecule that are attracted to electron-poor (electrophilic) regions, or are electron-pair acceptors.
• Polynucleophiles include, but are not limited to diols, triols, polyols, diamines, triamines, polyamines, dithiols, trithiols, polythiols, diamides, triamides, polyamides, diethers, triethers, and polyethers.
• lignocellulosic composite compositions that are useful in, among other things, providing composites such as wood composites that have improved performance characteristics while also minimizing environmental impact by using green substitutes in the adhesive component.
• compositions described herein comprise a lignocellulosic component, and an adhesive component that comprises a bis-electrophile and a polynucleophile.
• an adhesive component that comprises a bis-electrophile and a polynucleophile.
• the bis-electrophile is a dianhydride
• the polynucleophile is a polyol.
• Lignocellulosic components described herein comprise lignocellulosic material.
• Lignocellulosic material is typically derived from wood, but also can be derived from other materials, such as straw, flax residue, nut shells, cereal grain hulls, etc.
• the lignocellulosic component is typically wood flour, sawdust, wood strand, wood flakes, wood chips, wood fibers or straw.
• Non-lignocellulosic materials in flake, fibrous or other particulate form, such as glass fiber, mica, asbestos, rubber, plastics, etc. can also be mixed with the lignocellulosic material; however, such materials are not generally required for purposes of the compositions described herein.
• Exemplary lignocellulosic components for use in the compositions described herein are wood strand, wood flakes and wood chips.
• the polynucleophiles useful in the compositions described herein are molecules with two or more nucleophilic regions, i.e., two portions of the molecule that are attracted to electron-poor (electrophilic) regions, or are electron-pair acceptors.
• the polynucleophiles include, but are not limited to diols, triols, polyols, diamines, triamines, polyamines, dithiols, trithiols, polythiols, diamides, triamides, polyamides, diethers, triethers, and polyethers.
• Exemplary polynucleophiles for use in the compositions described herein are polyols, polyamines, polythiols, polyamides and polyethers.
• Suitable polynucleophiles may be polyols—polymeric alcohols, or organic compounds with two or more hydroxy groups.
• Suitable polyols include polyester polyols, polyether polyols, and combinations thereof.
• the polyol can be selected from the group of, but is not limited to, aliphatic polyols, cycloaliphatic polyols, aromatic polyols, heterocyclic polyols, and combinations thereof.
• suitable polyols are selected from the group of, but are not limited to, glycerols, propylene glycols, sucrose-initiated polyols, sucrose/glycerine-initiated polyols, trimethylolpropane-initiated polyols, and combinations thereof.
• mixtures of the polyols may be used.
• Mixtures of polyols may be used so as to improve on dispersability or solubility of a polyol. For example, it was found that it was possible to form a homogeneous mixture of SAA-100 in a dispersion of 10 wt % Mowiol® 40-88 in water but not in neat water.
• Suitable bis-electrophiles for use in the compositions described herein are molecules with at least two electrophilic regions, i.e., two portions of the molecule that are attracted to electron-rich (nucleophilic) regions, or are electron-pair receptors.
• Bis-electrophiles include diketones, diesters, and dianhydrides.
• a suitable bis-electrophile may include at least one cyclic structure that is opened when reacted with a nucleophile like the polynucleophile of the invention.
• An exemplary bis-electrophile is a dianhydride.
• Exemplary dianhydrides for use in the compositions described herein are shown in Table 2.
• compositions described herein are the proportion of adhesive component (comprising a bis-electrophile and a polynucleophile) in the lignocellulosic composite.
• the bis-electrophile and polynucleophile together may be present in from 1 to 10 parts per 100 PDW (parts dry weight of the lignocellulosic component in the composition). Alternatively, they are present in from about 2 to about 6 parts per 100 PDW, or from about 4 to about 6 parts per 100 PDW.
• compositions described herein are the ratio of polynucleophile to bis-electrophile in the adhesive component or lignocellulosic composite.
• the polynucleophile and bis-electrophile may be present in the adhesive component at a ratio of between 1:20 and 20:1 polynucleophile:bis-electrophile (mol:mol).
• they are present in a ratio of between 1:3 and 6:1 polynucleophile:bis-electrophile, or between 1:1 and 6:1 polynucleophile:bis-electrophile.
• accelerators of the invention are waxy acids or fatty acids, and may also be wax/organic acid mixtures.
• Preferred accelerators of the invention are C 8 -C 24 alkylcarboxylic acids.
• the C 8 -C 24 alkyl group of the accelerator is a linear or branched alkyl group which may optionally include 1, 2 or 3 unsaturated (double) bonds.
• the accelerator and polynucleophile may be present in the composite at a ratio of between 1:1 and 1:20 accelerator:polynucleophile (mol:mol). More preferably, they may be present in the composite at a ratio of between 1:2 and 1:10 accelerator:polynucleophile, and most preferably at a ratio of between 1:3 and 1:5.
• the lignocellulosic composite described herein may further comprise an additive component.
• Additive components are typically selected from the group of waxes, alcohols, parting agents, catalysts, fillers, flame retardants, water, plasticizers, stabilizers, cross-linking agents, chain-extending agents, chain-terminating agents, air releasing agents, wetting agents, surface modifiers, foam stabilizing agents, moisture scavengers, desiccants, viscosity reducers, reinforcing agents, dyes, pigments, colorants, anti-oxidants, compatibility agents, ultraviolet light stabilizers, thixotropic agents, anti-aging agents, lubricants, coupling agents, solvents, rheology promoters, adhesion promoters, thickeners, smoke suppressants, anti-static agents, anti-microbial agents, fungicides, insecticides, and combinations thereof.
• the additive component if employed, may be present in various amounts, and may include any combination of the aforementioned additives.
• Exemplary additives include waxes such as zinc stearate, stearamide (as Finawax S-90), Soy Wax, Slack Wax, and aliphatic alcohols such as n-hexanol or n-decanol.
• wax is included in the composite at a concentration of 0.5 to 4.0 wt %, preferably 1 to 3 wt %, most preferably 1.5 to 2 wt %.
• oriented strand boards composites formed from an adhesive component of dianhydride/polyol and lignocellulosic component wood strands.
• any adhesive component of the claimed invention could also be used with any lignocellulosic component, and the methods of making herein also apply thereto.
• the polyol is applied as an aqueous dispersion to the wood strand. Water content of the resulting mixture may then be adjusted by addition (to maintain flexibility of the wood strand) or removal by drying (to reduce reaction of the residual water with the dianhydride).
• the wood strand mixture is then coated with dry powdered dianhydride.
• the wood strand mixture is then formed and pressed using conventional press-to-thickness methods of forming a composite panel. Typical press times are 3 to 10 min, with typical press temperatures from 325 to 400° F.
• the polyol (or polynucleophile) is applied as a dry powder after addition of the wax and accelerator (if necessary or desired).
• the dry particle size may be 250 um or less, preferably 200 um or less, and most preferably 150 um or less.
• the polyol can be added using an air (venture) spray to the blender or by simple mechanical addition (e.g., pouring into a blender using a bucket).
• the moisture level is kept low ( ⁇ 4 weight %), preferably less than 2 weight %, and most preferably 1.5 weight % or less.
• the wood strand mixture is then coated with dry powdered dianhydride.
• the wood strand mixture is then formed and pressed using conventional press-to-thickness methods of forming a composite panel. Typical press times are 3 to 8 min, with typical press temperatures from 325 to 415° F.
• powdered polyol and powdered dianhydride are mixed together prior to mixing with the wood strands (ideally 4 hours or less at room temperature before application) and then applied to the strands before pressing at similar conditions.
• Small 13 cm ⁇ 13 cm panels of OSB were formed on a benchtop scale for formulation evaluation by panel density, flexural strength as determined by modulus of rupture (MOR), and 2-hr and 24-hr water uptake as determined by both increase in weight and swelling (increase in thickness).
• MOR modulus of rupture
• Panels were formed at 1 ⁇ 8′′ thickness, with resulting densities typically in the range of 50 to 70 lbs/cu ft. These densities are similar to densities for a commercial product such as medium density fiberboard (MDF) or hardboard.
• MDF medium density fiberboard
• the 1 ⁇ 8′′ panels have flexural strengths (modulus of rupture, or maximum stress to rupture) and water uptake, as measured by both weight gain and swelling (thickness increase) for 2 hr and 24-hr immersion, that demonstrate the structural and mechanical integrity of the composites appropriate for typical uses of OSB in the building or furniture trades or the like.
• Panels were also formed at 1 ⁇ 4′′ thickness, with densities in the range of 41 to 58 lbs/cu ft, more similar to densities of comparable commercial (Georgia Pacific) OSB that measure in the range 37 to 46 lbs/cu ft. Flexural strengths and water uptakes were used as a measure of structural and mechanical integrity, and are comparable to those of commercial OSB.
• An exemplary method of application of the adhesive composition is by spraying an aqueous dispersion of a polyol onto the wood strand, while mixing.
• the dianhydride is then mixed with the wood strand.
• the wood strand mixture is then formed, typically within an hour of preparing the wood strand mixture, and pressed-to-thickness under given conditions of time and temperature.
• Water content of as-received wood strand may be adjusted prior to the addition of the adhesive.
• as-received wood strand is dried at 100° C. to a 1 wt % water content.
• the water content of the wood strand following spraying with an aqueous mixture of polyol or dianhydride or other additive may be adjusted so as to render the wood strand sufficiently pliable for forming, but not so great as to cause excessive reaction of retained water with the dianhydride.
• the water content may be adjusted by addition of water to the strand, or be reduced, for example by drying the coated wood strand in a 50-60° C. oven, or by drying with the flow of hot air from a heat gun.
• Alternative methods of preparing the adhesive-coated wood strand such as application of the dianhydride as an aqueous dispersion, variation in drying procedures prior to forming the composite, or “one-pot” application of a mixed polyol and dianhydride dispersion in water result in composite panels that are comparable in density, flexural strength, and water uptake to those formed by the preferred procedure.
• Described herein is a method of forming an article, which can be the product or the composite article, with the product typically being formed as an intermediate to the formation of the composite article.
• the lignocellulosic component is provided from a variety of lignocellulosic sources, and can be formed from a variety of processes, as understood in the art.
• the adhesive component, and optional additive components are applied to the lignocellulosic component to form the product of the present invention.
• the non-lignocellulosic components can be applied to the lignocellulosic components at the same time, or can be applied to the lignocellulosic components at different times.
• an additive component is applied the lignocellulosic components prior to the adhesive component.
• an additive component is applied to the lignocellulosic component after the adhesive component.
• the adhesive component and an additive component are applied simultaneously to the lignocellulosic component.
• the non-lignocellulosic components can be applied to the lignocellulosic component by various methods, such as mixing, tumbling, rolling, spraying, sheeting, blow-line resination, blending (e.g. blow-line blending), etc.
• the non-lignocellulosic components and the lignocellulosic component can be mixed or milled together during the formation of a mass, also referred to as a binder-lignocellulosic mixture, mat, or “furnish”, as further described below.
• the non-lignocellulosic components are applied to the lignocellulosic component by a spraying, an atomizing or a fogging process, as understood in the art.
• the mass can then be formed into the product with a predetermined width and a predetermined thickness.
• the predetermined width and thickness of the mass are determined according to final widths and thicknesses desired for the composition article, as described further below.
• the accelerator may be applied in several ways.
• the accelerator is dissolved in an organic solvent (e.g., THF), optionally with a slack wax, and sprayed directly on the lignocellulosic component.
• the accelerator may be melted with Slack Wax and sprayed hot on the lignocellulosic component while it is mixing or tumbling.
• the accelerator may be mixed with an emulsified wax or “E-wax”.
• a solid accelerator such as stearic acid in flake form
• a solid accelerator can be milled to a fine particle size and then mixed with the lignocellulosic component separately or together with the other non-lignocellulosic components.
• the product can then be formed in various shapes, such as boards or panels, or formed into more complex shapes, by molding or extruding the product to form the composite article.
• the non-lignocellulosic components are sprayed, atomized, and/or fogged onto the lignocellulosic component while the lignocellulosic component is being agitated.
• Spraying, atomizing and fogging can occur via use of nozzles, such as one nozzle for each component supplied thereto, or nozzles that have two or more components premixed and supplied thereto.
• the components are generally applied by spraying droplets or atomizing or fogging particles of the non-lignocellulosic components onto the lignocellulosic component as the lignocellulosic component is being tumbled in a rotary blender or similar apparatus.
• the lignocellulosic component can be coated with the non-lignocellulosic components in a rotary drum blender equipped with at least one, typically at least two spinning disk atomizers. Tumblers, drums, or rollers including baffles can also be used, as understood in the art.
• the composite article is typically formed from the product, e.g. the mat, by compressing the mass at an elevated temperature and under pressure. Such conditions facilitate reaction of the binder composition to form the reaction product. Typically, heat is applied to the mass to facilitate curing. Press temperatures, pressures and times vary widely depending upon the shape, thickness and the desired density of the composite article, the size and type of the lignocellulosic component, the moisture content of the lignocellulosic component, and the other components employed.
• the press temperature for example, can range from about 100° C. to about 300° C. To minimize generation of internal steam and the reduction of the moisture content of the final composite article below a desired level, the press temperature is typically less than about 250° C. and most typically from about 180° C.
• the pressure employed is generally from about 300 to about 800 pounds per square inch (psi).
• the press time is from 120 to 900 seconds.
• the press time employed should be of sufficient duration to at least substantially cure the binder composition (in order to substantially form the reaction product) and to provide a composite article of the desired shape, dimension and strength.
• the press time depends primarily upon the panel thickness of the composite article produced.
• the press time is generally from about 200 seconds to about 300 seconds for a pressed composite article with about a 0.5′′ thickness.
• Wood strand composed of Aspen wood and wood fiber were obtained from Alberta Innovates—Tech Futures (Edmonton, Alberta, Canada), “AITF”, and used throughout the Examples below. Unless stated otherwise, all wood strand was used “dry as received”: no conditioning was done to alter the moisture content of the wood strand prior to being weighed in preparation for composite formation. Moisture content in dry as received wood strand was typically about 3%, as measured by weight before and after drying at 50° C. for 16 hr.
• Polyvinyl alcohol (PVA) polyols were obtained from several suppliers. “PVA-A”, 78% hydrolyzed, 6K Mw, was obtained from Acros Organics. Other PVAs were obtained from Sigma-Aldrich, including “PVA-B”, 87-89% hydrolyzed, 13-23K Mw; “PVA-C”, 99+% hydrolyzed, 89-98K Mw; and “PVA-D”, 99+% hydrolyzed, 85-124K Mw.
• Aqueous solutions of each PVA in water typically 5, 12.5, or 20 wt %) were prepared so as to facilitate application to the wood strand by spraying with an air brush.
• Mowiol® (the trade name for polyvinyl alcohol resins produced by Kuraray Europe GmbH) were obtained through Sigma-Aldrich. Mowiol® 8-88 (Mw ⁇ 67,000 g/mol), Mowiol® 18-88 (Mw ⁇ 130,000 g/mol), and Mowiol® 40-88 (Mw ⁇ 205,000 g/mol), are all 86.7-88.7 mol % hydrolyzed, with 10.0-11.6% residual acetyl content.
• SAA-100TM and SAA-101TM styrene allyl alcohol copolymers were obtained from LyondellBasell Industries (Houston, Tex.).
• SAA-100 is 70:30 (mole ratio) styrene:allyl alcohol, with a Number Average Molecular Weight (Mn) of 1500 and a Weight Average Molecular Weight (Mw) of 3000.
• SAA-101 is 60:40 (mole ratio) styrene:allyl alcohol, with Mn of 1200 and Mw of 2500.
• SAA-100 dispersions were prepared on a 100-mL scale. 30 g of SAA-100 was ground into a fine powder using a mortar and pestle. The SAA-100 was then transferred into a 250 mL one-neck round-bottom flask to which were added 30 g of a 10 wt % dispersion of Mowiol 40-88 in water, an additional 40 g deionized water, and approximately 150 g of 2.5 mm-diameter ceramic milling beads.
• a dispersion of (10:1) (w:w) SAA-100:Mowiol® 40-88 in water containing 33 wt % total solids was prepared similarly from 20 g finely ground SAA-100, 20 g of a 10% dispersion of Mowiol® 40-88 in water, 60 g deionized water, and approximately 150 g of 2.5 mm-diameter ceramic milling beads.
• a dispersion of (10:1) (w:w) SAA-101:Mowiol® 40-88 in water containing 22 wt % total solids was prepared similarly from 20 g of finely ground SAA-101, 20 g of a 10 wt % dispersion of Mowiol® 40-88 in water, 60 g deionized water, and approximately 150 g of ceramic milling beads.
• POVALTM resins poly(vinyl alcohol) water-soluble/dispersible synthetic resins
• Kuraray POVAL poly(vinyl alcohol) water-soluble/dispersible synthetic resins
• POVAL LM-10HD and POVAL LM-20 are both 38.0-42.0 mole % hydrolyzed. In 1:1 water:methanol at 20° C., LM-10HD has a 4.5-5.7 cps viscosity, whereas LM-20 has a 3.0-4.0 cps viscosity. (Molecular weights are not specified for the POVAL resins).
• POVAL LM-10HD was typically prepared in isopropanol:water by heating 30 g of Kuraray POVAL LM-10HD in 30 g isopropanol and 75 mL deionized water at 50° C. yielding a 22 wt % solution that was clear and fluid enough for spraying.
• POVAL LM-20 was prepared by heating 20 g of the polymer in 80 mL deionized water at 90° C. The polymer appeared to melt but not dissolve. A clear solution was formed on addition of 25 mL isopropanol, followed by an additional 10 g of POVAL LM-20 resulting in a 22 wt % solution that was clear and fluid enough for spraying.
• POVAL LM-10HD To prepare an even larger quantity of POVAL LM-10HD solution that was used for the pilot plant tests (AITF, Edmonton, Canada), 1.0 kg POVAL LM-10HD was added to 2300 g of 28 wt % isopropanol in water. The mixture was heated until clear at 60° C. for about 2 hr. The solution was cooled and transferred into a 12 L flask. The preparation was repeated a second time with 1.0 kg of POVAL LM-10HD and 2300 g of 28 wt % isopropanol in water, and a third time with 0.5 kg POVAL LM-10HD and 1550 g of 28 wt % isopropanol in water.
• EVALTM EVOH resins (crystalline ethylene:vinyl alcohol copolymers) were obtained from Kuraray (Antwerp, Belgium).
• EVOH C109B is a 35 mol % ethylene, and 65% vinyl alcohol copolymer (Mw not specified).
• EVOH C109B (0.5 g) was dissolved in about 8 mL of 80:20 isopropanol:water for spraying onto wood strands.
• Poly(vinyl butyral) powder was obtained from Scientific Polymer Products.
• the “PVB (SP2)” powder consists of 19% hydroxyls, 1% acetyl, and 80% butyral (Mw 260K).
• PVB (SP2) powder (0.5 g) was dissolved in approximately 10 mL of isopropanol for application using an air brush.
• BUTVAR® Aqueous Dispersion RS-261 (“BUTVAR RS-261”, a poly(vinyl butyral) dispersion) was obtained from Solutia Inc. (St. Louis, Mo.). It consists of at least 25% BUTVAR B-72, 58% water, 12% castor oil added as a plasticizer, and 2% sulfonic acids, petroleum, and sodium salts. BUTVAR B-72 consists of 17.5-20.0% polyvinyl alcohol, 80% polyvinyl butyral, and 0-2.5% polyvinyl acetate (Mw 170-250K). In some instances, BUTVAR RS-261 was diluted to 10 wt % in isopropanol to make it easier to apply to wood strands using an airbrush.
• SharkPelletsC3TM (100% post-consumer poly(vinyl butyral) pellets) were obtained from Shark Solutions A/S (Vipper ⁇ d, Denmark). SharkPellets contain a small amount of carbon black as a non-sticking additive. SharkPellets (1.2 g) were dissolved in approximately 40 mL isopropanol for spraying onto wood strands.
• Gelatin 200 Bloom food grade was obtained from Gelita. Gelatin was applied to wood strand as a dry powder. Soluble Starch, P.A., was obtained from Acros Organics (P/N AC17713) and was applied to wood strand as a dry powder. Stearamide was obtained as Finawax S-90 powder from American International Chemical, Inc. (Framingham, Mass.). Soy Wax flakes were obtained as EcoSoyaTM PB from Pro Chemical Dye (Somerset, Mass.). Soy Wax consists of saturated and unsaturated vegetable lipids, predominantly containing triglycerides, diglycerides and monoglycerides.
• SPP507-PVB A second poly(vinyl butyral), “SPP507-PVB”, was obtained from Scientific Polymer Products, Catalog Number 507.
• SPP507-PVB has Mw approximately 200K, and is 19% hydrolyzed, 1% acetate, and 80% butyral.
• BPDA Benzophenone-3,3′,4,4′-tetracarboxylic dianhydride
• Stearic Acid was purchased from Sigma-Aldrich (P/N W303518).
• Slack Wax trade name Prowax 563, was obtained from ExxonMobil, Imperial Oil, Petroleum and Chemical Division, Lubricants and Specialties (Calgary, Alberta, Canada).
• Wood strand measuring 5 cm in length or less is placed in a glass crystallizing dish. A polymer solution is sprayed onto the wood strand using an air brush, with intermittent mixing to have the polymer coat the strand evenly. The wood is allowed to dry either: under ambient conditions; at 50° C. overnight (16 hours); or using a heat gun, as noted in each Example.
• Residual Water ⁇ [(Dried weight of wood strand and Polymer) ⁇ (Weight of as-received wood strand) ⁇ (Dry weight of Polymer, determined from solution concentration and amount of solution)]/(Weight of as-received wood strand) ⁇ 100%.
• Residual Water results if the dried polyol-coated wood strand has a lower water content than the as-received wood strand.
• the polymer-coated wood strand is then placed in a plastic bag along with powdered anhydride.
• the contents of the bag are mixed by shaking, allowing the powder to coat the wood.
• Wood composite panels are pressed and formed from combined wood strand, adhesive, and additives, if any.
• a 13 cm ⁇ 13 cm square deckle box is set onto a sheet of quick release aluminum foil laid on a metal plate.
• the adhesive-wood strand mixture (“furnish”) is then added by hand to the prepared deckle box so as to have the wood strands lay flat and form a “mat”, with a relatively even distribution in the deckle box, so the resulting pressed material approximates the structure of commercially-prepared OSB composites.
• the deckle box is then removed, and the wood strand topped with a sheet of quick release aluminum foil and a second metal plate.
• the sandwiched material is set onto a press platen preheated to a selected temperature, and pressed for a given time and then immediately removed from the press.
• the wood strand mixture is pressed at a given pressure, typically 7000, 4000, or 2000 psi.
• the amount of wood strand is selected so as to result in a wood composite panel of approximately 1 ⁇ 8 inch thickness. If no specific pressure is recited, the mat was compressed with pressure sufficient to cause the two press plates to contact the shims (“press-to-thickness”). After pressing, pressure is released and the composite panel removed from the press while hot.
• Formed wood composite panels are allowed to sit at least overnight at ambient temperature and humidity before test samples are cut from the panels.
• Two test strips labeled “A” and “B”, each measuring nominally 9 cm ⁇ 4 cm, are then cut from the center of each formed composite panel.
• the test strips are used for determination of density, flexural strength, and water uptake, using methods similar to those described in ASTM D1037-12, “Standard Test Methods for Evaluating Properties of Wood-Base Fiber and Particle Panel Materials”.
• MOR Flexural Strength or Modulus of Rupture
• Water uptake is usually determined for only one test strip from each panel—typically the test strip with the larger MOR. The selected test strip is weighed to determine the initial mass. Thickness is measured along each of the two shorter (4-cm) edges and crosswise (transverse) across the shorter dimension; the three thickness measurements are averaged to determine the initial test strip thickness.
• test strip is then re-immersed in the deionized water and allowed to remain in the water for a total of 24 hours.
• the test strip is then patted with a paper towel to remove surface water, re-weighed, and thickness measured at each edge and the middle. The 24-hour water uptake was calculated as above.
• IB Internal bond strength
• the dried and PVA-coated wood strand was then dusted with an amount of 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BPDA) by sprinkling the fine BPDA powder over each of the dried, PVA-coated wood strand mixtures and then mixing all components so as to result in wood strand uniformly coated with the polyol and the dianhydride.
• BPDA 3,3′,4,4′-benzophenonetetracarboxylic dianhydride
• the resulting resinated wood strand (“furnish”) was then formed into a mat in a 13 cm ⁇ 13 cm square deckle box, and then pressed into a composite panel for 10 min at 7000 psi and 325° F.
• the data show that the panel strength increased with increasing PVA content in the adhesive, up to about 2.5:1 PVA:BPDA.
• the flexural strength decreased from the maximum for panels formed for which the PVA:BPDA ratio was higher, to the point where the panel with no BPDA barely held together.
• the water uptake data display a similar trend.
• the water uptake as measured both by weight and thickness swelling, was reduced with increasing PVA and reached a minimum at about 2.5:1 PVA:BPDA.
• the panel was intact after 2-hr water immersion, but swelled and began to fall apart after 24-hr water immersion.
• wood strand (51.0 g) measuring 5 cm in length or less was placed in a glass crystalizing dish, and a PVA solution was sprayed onto the wood strand using an air brush. If the PVA required dilution with water to assist with spraying, then the additional water was removed through evaporation at ambient temperatures.
• the PVA-coated wood strand was then placed in a plastic bag along with BPDA. The contents of the bag were mixed allowing the powder to coat the wood.
• the wood strand mixture was then formed and pressed in a 13 cm ⁇ 13 cm deckle box for 10 min at 7000 psi and 325° F. or 350° F. to result in a composite panel approximately 1 ⁇ 8′′ thick.
• Panels comprised of PVA adhesive lacking dianhydride had flexural strengths 10 N/mm 2 or less, significantly lower than those containing dianhydride. Panels comprised of PVA adhesive lacking dianhydride completely fell apart after 2 h immersion in water.
• wood strand (51.0 g) was sprayed with an amount of either (a) a 20% solution of 78% hydrolyzed, 6K Mw PVA in water, or (b) a 12.5% solution of 87-89% hydrolyzed, 13-23K Mw PVA in water.
• the PVA-coated wood strand was dried in a 50° C. oven overnight (16 h), then dusted with dianhydride.
• the wood strand mixture was then formed and pressed for 10 min at 7000 psi and 325° F. to result in a panel approximately 1 ⁇ 8′′ thick.
• wood strand 51 g was sprayed with a dispersion of a selected polyol or polyol mixture using an air brush. Some or all of the water was then removed by drying in a 50° C. oven overnight (16 h) or through evaporation. The polymer coated wood strand was then dusted with an amount of BPDA, and formed into a 13 cm ⁇ 13 cm mat and pressed for 10 min at either 2000 or 7000 psi and at 325° F. or 350° F. to result in a panel approximately 1 ⁇ 8′′ thick.
• Panels comprised of PVA generally had higher flexural strength and lower water uptake than those comprised of SAA.
• wood panels were formed from 51.0 g wood strand sprayed with 1.82 g of a 12.5% (w/w) solution of 13-23K, 87-89% hydrolyzed PVA, and allowed to dry overnight (16 hr) at ambient temperature, and then weighed to determine residual water.
• the wood strand was then dusted with 1.85 g BPDA and with an amount of 1-hexanol or 1-decanol equivalent to either 10 or 30 mole % of BPDA, and then formed in a 13 cm ⁇ 13 cm deckle box and pressed into panels for 10 min at 7000 psi and 325° F. to result in a panel approximately 1 ⁇ 8′′ thick.
• compositions of composites comprised of PVA-B. All composites formed in a 13 cm ⁇ 13 cm mat, and pressed for 10 min at 7000 psi and 325° F. to result in a panel approximately 1 ⁇ 8′′ thick.
• Wood Furnish Composition Adhesive Wood parts per Strand 100 Parts Dry PDW Polyol: Parts Alcohol Weight wood Dianhydride Alcohol Panel I.D.
• wood strand 51 g was sprayed with an amount of 20% PVA (6K Mw, 78% hydrolyzed) solution in water, using an airbrush.
• the PVA-coated wood strand mixture was either allowed to dry overnight at ambient temperature, dried overnight (16 hr) at 50° C., dried with a heat gun, or dried at ambient temperatures for a time sufficient to leave the desired amount of residual water on the wood strand.
• the wood strand mixture was then weighed to determine the residual water content.
• the wood strand was then dusted with an amount of BPDA, formed in a 13 cm ⁇ 13 cm deckle box, and pressed into panels.
• the press temperatures were selected from 325° F., 350° F., 375° F. or 400° F., in combination with press times of either 5 or 10 min.
• the composite panels were pressed at 2K psi, 4K psi, or 7K psi, resulting in formed panels of approximately 1 ⁇ 8′′ thickness.
• wood strand 51 g was sprayed with a polyol disperion using an air brush, and then additional water or solvent was removed through evaporation using a heat gun. Soluble Starch and Gelatin were applied as dry powders rather than as a dispersion, and no drying was required.
• the coated wood strand was then dusted with BPDA, formed in a 13 cm ⁇ 13 cm deckle box and then pressed for 10 min at 7000 psi, and at 325° F. or 350° F. to result in a panel approximate 1 ⁇ 8′′ thick.
• Compositions, press temperature, densities, flexural strength, and water uptake for the thus-formed composite panels are given in Table 16 and Table 17.
• wood strand 51 g measuring 5 cm in length or less was placed in a glass crystalizing dish, and the neat diol, or triol, or mixture of polyols was mixed thoroughly with the wood strand.
• the polyol-coated wood strand was then dusted with an amount of BPDA, and then formed by pressing for 10 min at 7000 psi and 325° F. to result in a panel approximately 1 ⁇ 8′′ thick.
• wood strand 75 g was sprayed with a solution of a given polyol using an air brush.
• the polyol-coated wood strand was then dried with a heat gun, dusted with an amount of BPDA, formed into a mat in a 13 ⁇ 13 cm deckle box, and then pressed into a composite panel for 5 min at 400° F., using the press-to-thickness procedure with shimming to 1 ⁇ 4.
• wood strand (65 g) was sprayed with a solution of a selected polyol using an air brush.
• the polyol-coated wood strand was dried with a heat gun, and then weighed to determine residual water content.
• the dried, polymer-coated wood strand was then dusted with an amount of BPDA, and then pressed into a composite panel for 10 min at 400° F. with shimming to 1 ⁇ 4′′ thickness.
• wood strand 60 g was sprayed with a solution of a given polyol using an air brush.
• the polyol-coated wood strand was formed into a composite without removal of water, for others the wood strand mixture was dried with a heat gun.
• Each wood strand mixture was then dusted with the appropriate amount of BPDA, and then formed and pressed into a composite panel for a given time of either 5, 8, or 10 min, at 400° F. using the press-to-thickness procedure with shimming to 1 ⁇ 4′′.
• wood strand 60 g was sprayed with a solution of a selected polymer using an air brush.
• the water or solvent was allowed to evaporate under ambient conditions, and for others the wood strand mixture was dried with a heat gun.
• Each wood strand mixture was then dusted with the appropriate amount of BPDA, and then formed and pressed into a composite panel for a given time from 5 to 10 min, at 400° F. and using the press-to-thickness procedure with shimming to 1 ⁇ 4′′.
• Additives were applied to the wood strand mixture using different methods depending on the additive:
• Zinc stearate was dusted onto the polymer-coated wood strand in combination with BPDA.
• the wood strand was first sprayed with polymer dispersion, and then with Finawax S-90 as a 27% aqueous dispersion.
• the wood strand mixture was then dried with a heat gun, dusted with BPDA, formed and pressed.
• soy wax For application of soy wax, the polymer dispersion was mixed with the soy wax then heated until the wax melted creating a polymer fluid/wax dispersion. The mixture was then sprayed onto the wood strand. If needed, an additional amount of water (or isopropanol for application in combination with the polyol LM-10HD) was added to improve the spray behavior. All of the water/solvent introduced along with the polymer/wax fluid was evaporated using a heat gun. The wood strand mixture was then dusted with BPDA, formed and pressed.
• wood strand (180 g) was sprayed with a solution of a selected polymer using an air brush. Finawax S-90 as a 27% aqueous dispersion was then sprayed onto the wood strand.
• the wood strand mixture was then dried with a heat gun, and then dusted with BPDA.
• approximately one-third (approximately 64 g) of the wood strand mixture was formed and pressed into a composite panel for 10 min at 400° F. using the press-to-thickness procedure with shimming to 1 ⁇ 4′′ thickness.
• Panels formed from aged wood furnish all had comparable flexural strength to panels formed within one hour of mixing the wood furnish.
• BPDA Dry, powdered BPDA was added to a given amount of polyol solution.
• the polyol/BPDA mixtures were stirred for 0, 2 and 4 hours, and then applied with an airbrush to 65 g of wood strand.
• the coated wood strand was then dried with a heat gun, and then formed and pressed into a 13 cm ⁇ 13 cm composite panel for 10 min at 400° F. using the press-to-thickness procedure with shimming to 1 ⁇ 4′′.
• a polyol solution of 33% (10:1 w/w) SAA-100:Mowiol® 40-88 in water was applied with an airbrush to 65 g of wood strand.
• the coated wood strand was then dried with a heat gun.
• the polyol-coated wood strand was then sprayed with a dispersion of 0.65 g of BPDA in 3.25 g water, which was either freshly prepared, or aged for 1, 2, or 4 hours with stirring.
• the wood strand mixture was in some instances again dried with a heat gun.
• the wood strand mixture was then formed and pressed into a 13 ⁇ 13 cm composite panel for 5 min at 400° F. using the press-to-thickness procedure with shimming to 1 ⁇ 4′′.
• the polyol dispersion was sprayed onto 65 g wood strand.
• BPDA was then suspended in 6.5 g water and sprayed onto the wood strand.
• the mixtures were then dried with a heat gun set to medium until the total weight was no more than 1 g greater than the combined weight of the wood strand, dry weight BPDA, and dry weight polyol.
• the wood strand mixture was then formed into a 13 ⁇ 13 cm mat and pressed for 10 min at 400° F. using the press-to-thickness procedure with shimming to 1 ⁇ 4′′.
• a bulk quantity of wood strand was conditioned by heating in a convection dryer at 100° C. to reduce residual moisture content to approximately 1 wt %.
• Conditioned wood strand (20.0 kg) consisting of approximately 19.8 kg dry weight wood strand and 0.2 kg water was then introduced into a rotating drum blender.
• a prepared polyol dispersion in water was re-mixed with a model HSM-100LSK Ross Shear Mixer for approximately 3 min at 5000 rpm so as to ensure homogeneity of the dispersion.
• the drum blender was then closed, rotation started, and then an amount of Slack Wax equal to 1 wt % of the dry weight wood strand, equivalent to 198 g Slack Wax per 20.0 kg of conditioned wood strand (where 20.0 kg conditioned wood strand consists of 19800 g dry weight wood strand and 200 g water) was added over the course of approximately 2 min by atomization using standard methods.
• the selected aqueous polyol dispersion was then sprayed onto the wood strand by introduction by peristaltic pump addition through a Concord Model EL-3 Spinning Disk Applicator operating at approximately 10,000 rpm. The addition took place over the course of approximately 1-2 min at room temperature, all the while continuing to blend the wood strand mixture.
• the wood strand mixture was then blended for an additional 5 min at room temperature. Residual water content was then measured, and adjusted by the addition of water if necessary to achieve a water content sufficient to keep the wood pliable.
• a pre-weighed amount of dry, powdered BPDA was then introduced into the drum blender by air aspiration over the course of 2 min while rotating the drum.
• the wood strand mixture was then removed from the drum blender, and kept in 30-gallon covered garbage bins until formed and pressed into composite panels, typically within 45 min to 1 hr of mixing.
• the mat was pressed into a composite panel for a given time, ranging from 3 to 10 min, as given in Table 35, at a nominal press platen temperature of 400° F. and using a press-to-thickness procedure with shimming to 7/16′′ thickness. Press Pressure, Layer Thickness, Core Center Temperature, Core Center Gas Pressure, Core Corner Temperature, and Core Corner Gas Pressure were monitored during the press procedure. Press pressure typically reached a maximum of about 700 psi in less than 1 min. The core temperatures typically reached the 400° F. platen temperature at approximately 9 min.
• the panel edges were then removed by trimming approximately 4 in from each side.
• the mass of a resulting composite panel before trimming was typically approximately 4.9 kg.
• the mass loss of about 0.2 kg from the 5.1 kg of the pressed mixture was attributed largely to loss of water, as evidenced by an increase in the measured gas pressure during the initial forming of the composite as the core temperature increased, followed by a gradual decrease in the gas pressure as water desorbed from the composite.
• Each formulation consisting of conditioned wood strand (1% moisture content), Slack Wax, polyol dispersion, and BPDA, was formed and pressed into three composite panels, the first panel pressed for 5 min, the second pressed for 10 min, and the third pressed either for 7.5 min or for 3 min.
• AT AITF Six specimens of face dimension 50 mm ⁇ 50 mm, nominally 7/16′′ thick, were cut from the panel immediately after forming, weighed and measured so as to determine density, and the internal bond strength, “IB HOT” was then determined for each of the six specimens. The IB “HOT” was determined for only a selection of panels.
• the internal bond strength was determined for all panels using six freshly-cut specimens of face dimension 50 mm ⁇ 50 mm, nominally 7/16′′ thick after approximately 2 days of aging at ambient temperature and humidity.
• Panels were conditioned at 65% relative humidity and 68° F. according to ASTM D1037-12, and then three specimens of face dimension nominally 12.4 in [315 mm] ⁇ 3 in [74 mm] were cut from each panel, weighed and measured to determine density. The three specimens were then subjected to a 2-hr boil in water, and MOR determined using a sample span of 10.4 in [264 mm] as given in the methods of Canadian Standard Association CSA O437.1-93 (3.1.4). Some of the specimens fell apart during the boil, as given in Table 35.
• Densities and flexural strengths were determined from nominally 4 cm ⁇ 7-7.5 cm samples cut from near the center of the wood composite panels approximately 1 week after the panels were formed, using the procedures of Example 1. Water uptake at 2 hr and 24 hr was determined from nominally 5.5 cm ⁇ 3.5 cm samples, using the procedures of Example 1.
• compositions of the wood furnish batches are given in Table 35. Each batch was pressed into three composite panels. Press conditions, densities, flexural strength, internal bond strength, and water uptake for the resulting composite panels are given in Table 36 and Table 37.
• AITF Analytics for Pilot Plant
• All composite panels formed from 5.1 kg of wood furnish in a 34 in ⁇ 34 in deckle box and pressed at 400° F. for the given time, with shimming to 7/16′′.
• Composite Panel Analytics (AITF data) Wood Bond Furnish Density Internal Bond Density Durability Composition Press (prior to Strength after Internal Bond (prior to (MOR after ID (from time IB test) conditioning Strength HOT 2-hr boil) 2-hr boil) Panel I.D. Table 35) (min) (lb/cu. ft) (MPa) (MPa) (lb/cu.
• AITF-2A-1 AITF-2A 10 38.3 ⁇ 5.5 0.232 ⁇ 0.052 0.216 39.1 ⁇ 1.1 4.4 ⁇ 0.5 AITF-2A-2 AITF-2A 5 39.4 ⁇ 2.8 0.200 ⁇ 0.034 38.3 ⁇ 0.9 1.8 ⁇ 0.2 AITF-2A-3 AITF-2A 7.5 36.0 ⁇ 3.0 0.228 ⁇ 0.018 39.4 ⁇ 0.9 3.4 ⁇ 0.8 AITF-2B-1 AITF-2B 10 41.4 ⁇ 3.9 0.352 ⁇ 0.071 0.301 39.3 ⁇ 3.3 5.7 ⁇ 1.0 AITF-2B-2 AITF-2B 5 38.1 ⁇ 2.5 0.283 ⁇ 0.038 37.7 ⁇ 0.5 1.2 ⁇ 0.2 AITF-2B-3 AITF-2B 7.5 36.9 ⁇ 3.3 0.279 ⁇ 0.061 36.7 ⁇ 0.9 3.4 ⁇ 0.4 AITF-2C-1 AITF-2C 10 39.3 ⁇ 3.4 0.340
• the resinated wood strand of was aged for 31 days, and was then formed into a 13 ⁇ 13 cm mat and pressed for 10 min at 400° F. and using the press-to-thickness procedure with shimming to 1 ⁇ 2′′.
• a bulk quantity of Aspen OSB wood strand was filtered using a 3 ft ⁇ 8 ft BM&M deck screener with a 0.125 in screen hole size.
• the filtered wood strand was then conditioned by heating in a convection dryer at 100° C. to reduce residual moisture content to 1 wt %.
• Twenty kilograms of conditioned wood strand consisting of approximately 19.8 kg dry weight wood strand and 0.2 kg water was then introduced into a rotating drum blender.
• Complete OSB wood composite formulations and press specifications are shown in Table 39.
• Prowax 563 1 part per 100 PDW wood strand, equivalent to 198 g Prowax 563 per 20.0 kg of conditioned wood strand, was heated to melt (80-90° C.).
• An amount of stearic acid equal to 0-2 parts per 100 PDW wood strand was heated in a separate container until completely melted. The stearic acid was then added to the Prowax 563 and mixed until homogenous. The drum blender was closed, rotation started, and the Prowax 563 and stearic acid melt mixture was added over the course of approximately 1-2 min using standard methods for addition of a heated material.
• a pre-weighed amount of dry, powdered BPDA equal to 0.05-0.80 parts per 100 PDW wood strand was then introduced into the drum blender by air aspiration over the course of 2 min, while rotating the drum.
• the wood strand mixture was then removed from the drum blender, and kept in 30-gallon covered garbage bins until formed and pressed into composite panels, typically within 45 min to 1 hr of mixing.
• the deckle box was then removed, the wood strand mat was covered with a non-stick polytetrafluorethylene (PTFE) sheet, and the layer introduced into a 3-ft hot oil press. Probes were inserted into the wood strand mat in order to monitor core gas pressure and temperature at the center and one corner during panel formation.
• the desired density was 39.0 lb/ft 3 and thickness was 0.437 in.
• the mat was pressed into a composite panel using a 3-step procedure consisting a “close time,” in which the pressure is gradually increased until the mat is compressed to the thickness of the shims; a “cook time” or “hold time,” in which the platens are held to the shim distance; and a “degas time,” in which the pressure is gradually released.
• Panels were pressed at a nominal press platen temperature of 415° F. and using a press-to-thickness procedure with shimming to 0.437 in thickness. Press pressure, layer thickness, core center temperature, core center gas pressure, core corner temperature, and core corner gas pressure were monitored during the press procedure. Press pressure typically reached a maximum of about 700 psi in less than 1 min. After pressing for the given time, the press pressure was released, and the wood composite panel was removed from the press while still hot. Resulting panel density ranged from 37.6-40.1 lb/ft 3 .
• a bulk quantity of MDF wood fiber was processed using a Pallman PR32 refiner.
• the filtered wood strand was then conditioned by heating in a convection dryer at 100° C. to reduce residual moisture content to 1 wt %.
• Twenty kilograms of conditioned wood strand consisting of approximately 19.8 kg dry weight wood strand and 0.2 kg water was then introduced into a rotating drum blender.
• Complete MDF wood composite formulations and press specifications are shown in Table 41.
• Prowax 563 1 part per 100 PDW wood strand, equivalent to 0.198 kg Prowax 563 per 20.0 kg of conditioned wood fiber, was heated to melt (80-90° C.).
• An amount of stearic acid equal to 2 parts per 100 PDW wood strand was heated in a separate container until completely melted. The stearic acid was then added to the Prowax 563 and the mixture was stirred until homogenous.
• the drum blender was closed, rotation started, and the Prowax 563 and stearic acid melt mixture was added over the course of approximately 1-2 min using standard methods for addition of a heated material.
• SPP507-PVB dry powder equal to 5 parts per 100 PDW wood strand was then introduced into the drum blender by air aspiration over the course of 2 min while rotating the drum.
• an amount of dry, powdered BPDA equal to 0.10 or 0.50 parts per 100 PDW wood strand was then introduced into the drum blender by air aspiration over the course of 2 min while rotating the drum.
• the wood fiber mixture was then blended for an additional 5 min at room temperature.
• the wood fiber mixture was then removed from the drum blender, and kept in 30-gallon covered garbage bins until formed and pressed into composite panels, typically within 45 min to 1 hr of mixing.
• the wood fiber mats were pressed into a composite panels using a 3-step procedure consisting of a “close time”; “cook time”; and “degas time”.
• the nominal press platen temperature was 415° F., and the mats were pressed using a press-to-thickness procedure with shimming to 0.138 in thickness. Press pressure, layer thickness, core center temperature, core center gas pressure, core corner temperature, and core corner gas pressure were monitored during the press procedure. After pressing for the given time, the press pressure was released and the thus-formed wood composite panel removed from the press while still hot. Resulting panel density ranged from 49.2-59.3 lb/ft 3 .
• MDF panels were sanded to 0.125 in prior to being cut to 18 in ⁇ 18 in. Panels were tested for Modulus of Elasticity (MOE), MOR, IB, TS, WA, and MC as per the ANSI A208.2—2009 MDF test standard. All properties of the MDF wood composites are shown in Table 42.
• MOE Modulus of Elasticity

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